Dynamic mimicry in an Indo-Malayan octopus

During research dives in Indonesia (Sulawesi and Bali), we filmed a distinc tive long-armed octopus, which is new to science. Diving over 24h periods r evealed that the 'mimic octopus' emerges during daylight hours to forage on sand substrates in full view of pelagic fish predators. We observed nine i ndividuals of this species displaying a repertoire of postures and body pat terns, several of which are clearly impersonations of venomous animals co-o ccurring in this habitat. This 'dynamic mimicry' avoids the genetic constra ints that may limit the diversity of genetically polymorphic mimics but has the same effect of decreasing the frequency with which predators encounter particular mimics. Additionally, our observations suggest that the octopus makes decisions about the most appropriate form of mimicry to use, allowin g it to enhance further the benefits of mimicking toxic models by employing mimicry according to the nature of perceived threats.